29 research outputs found
Vacuolar (lysosomal) trehalase of Saccharomyces cerevisiae
In the yeast Saccharomyces cerevisiae the PEP4 gene product, protease A, is responsible for activating all soluble vacuolar (lysosomal) enzymes. These vacuolar enzymes remain inactive in pep4 mutants. Vacuolar trehalase activity was diminished in such mutants as well. This suggests that the vacuolar (lysosomal) trehalase is processed in a manner similar to other vacuolar enzymes in S. cerevisiae .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41331/1/284_2005_Article_BF01589375.pd
Preparation of Saccharomyces cerevisiae Expression Plasmids
Expression plasmids for Saccharomyces cerevisiae offer a wide choice of vector copy number, promoters of varying strength and selection markers. These expression plasmids are usually shuttle vectors that can be propagated both in yeast and bacteria, making them useful in gene cloning. For heterologous production of membrane proteins, we used the green fluorescent protein (GFP) fusion technology which was previously developed in the Escherichia coli system. We designed an expression plasmid carrying an inducible GAL1 promoter, a gene encoding a membrane protein of interest and the GFP-octa-histidine sequence. Here we describe construction of multi-copy yeast expression plasmids by homologous recombination in S. cerevisiae. © 2012 Springer Science+business Media, LLC.N
Assessment of Digital PCR as a Primary Reference Measurement Procedure to Support Advances in Precision Medicine
BACKGROUND: Genetic testing of tumor tissue and circulating cell-free DNA for somatic variants guides patient
treatment of many cancers. Such measurements will be
fundamental in the future support of precision medicine.
However, there are currently no primary reference measurement procedures available for nucleic acid quantification that would support translation of tests for circulating tumor DNA into routine use.
METHODS: We assessed the accuracy of digital PCR (dPCR)
for copy number quantification of a frequently occurring
single-nucleotide variant in colorectal cancer (KRAS
c.35GA, p.Gly12Asp, from hereon termed G12D) by
evaluating potential sources of uncertainty that influence
dPCR measurement.
RESULTS: Concentration values for samples of KRAS
G12D and wild-type plasmid templates varied by 1.2-
fold when measured using 5 different assays with varying
detection chemistry (hydrolysis, scorpion probes, and intercalating dyes) and 1.3-fold with 4 commercial
dPCR platforms. Measurement trueness of a selected
dPCR assay and platform was validated by comparison
with an orthogonal method (inductively coupled plasma
mass spectrometry). The candidate dPCR reference measurement procedure showed linear quantification over a
wide range of copies per reaction and high repeatability
and interlaboratory reproducibility (CV, 2%â 8% and
5%â10%, respectively).
CONCLUSIONS: This work validates dPCR as an SItraceable reference measurement procedure based on
enumeration and demonstrates how it can be applied for
assignment of copy number concentration and fractional
abundance values to DNA reference materials in an aqueous solution. High-accuracy measurements using dPCR
will support the implementation and traceable standardization of molecular diagnostic procedures needed for
advancements in precision medicine